Biologically compatible metallic meshes capable of being formed and contoured to the three-dimensional skeletal anatomy are known for surgical use. These meshes have been employed in osteosynthesis to rejoin and repair bone discontinuities resulting from trauma (i.e., fractures) and/or surgical procedures wherein osteotomies of the bone are necessary to performing the procedure.
Various configurations of contourable fixation devices have been used that are commonly secured to a region of bone with fasteners, for example bone screws. One class of contourable fixation device includes closed, solid construct meshes that are formed by machining, chemically etching, or otherwise creating a plurality of circular fastener openings into a generally square and flat sheet of material. These closed, solid construct meshes have limited flexibility and limited three-dimensional contourability due to their generally solid or closed structures. Accordingly, these closed, solid construct meshes can be difficult to three-dimensionally contour to correspond closely to a geometry that matches a geometry of an irregular or intricate portion of skeletal anatomy while avoiding kinking. Kinking is undesirable because it can cause a non-aesthetic appearance, soft tissue irritation, and other problems.
To attempt to eliminate the kinking problem and improve contourability, surgeons typically find it necessary to cut out multiple and/or extensive portions of the closed, solid construct meshes. FIG. 1 shows an example of a prior art closed, solid construct mesh 20 having triangular relief cuts 22 typically made by surgeons for applying this type of mesh to a frontal region of a skull. One drawback of making such customized relief cutouts is extended surgical time. Another drawback is that the cutouts themselves reduce the strength of the final mesh construct because the narrow section at the center of the mesh along line A-A has decreased flexural rigidity.
Another class of contourable fixation device is characterized by an open-structured, highly contourable mesh for example as disclosed in U.S. Pub. Nos. 2005/0149032 and 2008/0009872, the disclosures of which are hereby incorporated by reference in their entireties. FIG. 2 shows an example of a prior art open-structured, highly contourable mesh 30 in an initial rigid and flat two-dimensional configuration (hereinafter initial flat configuration). As shown in FIG. 2, the open-structured, highly contourable mesh 30 includes a plurality of spaced-apart fastening plates 32 (hereinafter plates), deformable links 34 (hereinafter links) interconnecting the plates 32, and openings 36 interspersed between the plates 32. Additionally, the open-structured, highly contourable mesh 30 can define holes 38 that extend through at least some of the plates 32. The holes 38 are configured to receive a fastener, such as a bone screw or tack, to secure the open-structured, highly contourable mesh 30 to a target region of bone.
The openings 36 may be defined by at least a portion of both the links 34 and the plates 32. The openings 36 provide space within the open-structured, highly contourable mesh 30 to allow the links 34 to be deformed in three dimensions. Accordingly, the open-structured, highly contourable mesh 30 is configured to be three-dimensionally contoured without kinking, more easily than the closed, solid construct mesh 20.
Typically, contourable fixation devices, such as the open-structured highly contourable mesh 30 discussed above, are provided to a surgeon housed in a sterile packaging in the initial flat configuration. Providing the contourable fixation device in the initial flat configuration may require the surgeon to spend time during the surgery contouring the fixation device to correspond to the anatomy of the target region of bone to which the fixation device is to be secured.
The process for a surgeon contouring the fixation device during surgery, to match the anatomy of an individual patient, may require a number of lengthy steps including: determining the implant reception site on the bone and the final three-dimensional shape of fixation device based on the anatomical three-dimensional shape of the target region of bone; heating the fixation device to above its glass transition temperature (by any suitable means such as a hot water or saline bath, hot air gun, bender/cutter iron, etc.) to make the fixation device malleable; placing the fixation device directly on the bone reception site and contouring the fixation device to have a desired three-dimensional shape; and cooling the fixation device by allowing its temperature to fall below the glass transition temperature whereupon the mesh returns to a rigid condition and holds the three-dimensional contoured shape.
Thus, an atomically-shaped fixation device that is available for use by a user, such as a surgeon, prior to surgery, without the need for extensive bending or other modification by the surgeon during surgery, and that conforms to a predetermined averaged geometry of a bone region can result in improved aesthetic results as well as a reduction of time and cost associated with a surgical procedure in which the fixation device is used to rejoin and repair bone discontinuities.